docs: def show_logs(self, selected_nodes_names=None):
          """
          Shows logs of nodes in this cluster, by default, with multitail.
          If you need to alter the command or options, change CCM_MULTITAIL_CMD .
          Params:
          @selected_nodes_names : a list-like object that contains names of nodes to be shown. If empty, this will show all nodes in the cluster.
          """
  
          if selected_nodes_names is None:
              selected_nodes_names = []
  
          if len(self.nodes) == 0:
              print_("There are no nodes in this cluster yet.")
              return
  
          nodes = sorted(list(self.nodes.values()), key=lambda node: node.name)
          nodes_names = [node.name for node in nodes]
  
          names_logs_dict = {node.name: node.logfilename() for node in nodes}
          if len(selected_nodes_names) == 0: # Parameter selected_nodes_names is empty
              return names_logs_dict.values()
          else:
              if set(selected_nodes_names).issubset(nodes_names):
                  return [names_logs_dict[name] for name in selected_nodes_names]
              else:
                  raise ValueError("nodes in this cluster are {}. But nodes in argments are {}".format(
                      nodes_names, selected_nodes_names
                  ))